This invention relates generally to an improvement in the manufacture of braided, reinforced hose, and more particularly to a braiding nose for forming a braided layer on the exterior of a flexible hose.
Commercially available hydraulic high pressure hoses are typically manufactured by extruding an elastomeric material to form a tube having the desired interior diameter and wall thickness. A braid is then applied to the exterior of the tube by a maypole type braider which utilizes a plurality of carriers to supply strands of wire, typically brass plated high tensil steel wire.
In order to form a uniform braid, the wire must be maintained under tension which exerts forces on the exterior of the tube. The braiding forces tend to distort and collapse the tube during the manufacturing process. In order to resist the braiding forces, the tube is typically frozen with liquid nitrogen prior to the braiding process. The tube to be braided is pulled through a cooling tube with a controlled flow of liquid nitrogen which freezes and hardens the uncured elastomer and provides a hard surface which will resist deformation during braiding. The braided hose is then crossheaded on an extruder and the cover applied. The hose is covered in a lead or thermoplastic sheath and cured in an autoclave with high pressure steam.
The prior art braiding machines include a mandrel on which the braided reinforcement is formed. The mandrel extends through a guide ring. A plurality of elongated strands of metallic wire are drawn from a plurality of bobbins carried on rotating spindles on the braiding machine and are directed in a predetermined pattern across the guide ring and onto the mandrel. Half of the bobbins are rotating in an opposite direction relative to the other half so that the strands of wire are spirally wrapped on the mandrel in an alternating overlapping interwoven relationship to continuously produce the braided tubular member. The strands are positioned in abutting relationship with one another to form a close knit braid which has a total initial coverage on the mandrel with no openings therebetween. As the braid is formed, it is drawn off the end of the mandrel and onto the outer surface of an elastomeric tube which is being drawn through the center of the hollow mandrel.